Loft Insulation Estimator
Calculate rolls and energy savings for a warmer, cheaper home.
Insulation Needed
Lay the first layer between the joists, and the second layer at right angles (perpendicular) across the joists. This helps to reduce "thermal bridging" through the timber.
Home Efficiency: The Power of Loft Insulation
Stopping the Escape
Heat rises, and in an uninsulated home, up to 25% of your heating budget disappears straight through the roof. Loft insulation is one of the most cost-effective home improvements you can make, often paying for itself in less than two years through lower energy bills.
The current UK standard is 270mm of mineral wool. Our **loft insulation calculator** helps you determine how many rolls you need to buy to reach this target.
UK Insulation Targets
Financial & EPC Benefits
Beyond the immediate monthly savings on your gas or electric bill, upgrading your loft insulation is one of the easiest ways to improve your home's **Energy Performance Certificate (EPC)** rating. A higher EPC rating can increase your property's value and is now a legal requirement for landlords in the UK.
Cross-Layering
To get the best performance, lay your top layer of insulation at a 90-degree angle to the joists. This covers the timber, which acts as a 'thermal bridge' (a path for heat to escape).
Recessed Downlights
Never lay insulation directly over recessed ceiling lights unless they are 'insulation coverable' or fitted with an intumescent fire hood. Doing so can cause the lights to overheat and pose a fire risk.
Pro Tip: Ventilation is Key
An insulated loft is a cold loft. Ensure you don't block the soffit vents at the edges of your roof. Without airflow, the moisture from your house will condense on the cold roof timbers, leading to damp and wood rot.
Loft Insulation FAQ
Technical Disclaimer
Annual savings are estimates based on Energy Saving Trust data for a typical UK semi-detached house. Actual savings depend on your heating fuel type, lifestyle, and local energy tariffs. Always wear a mask, gloves, and goggles when handling mineral wool insulation.